Non-toxic rubber-based composition and method for making the rubber based composition

ABSTRACT

A non-toxic rubber-based composition for use in manufacturing toys which contains styrene butadiene rubber, naphthene oil, ester gum, calcium carbonate and a coloring agent, and a method for making same.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a non-toxic, stickyrubber-based composition and, more particularly, is concerned with amethod for making the non-toxic rubber-based composition for use intoys.

2. Description of the Prior Art

Recently, a toy made of a rubber-based composition has gained immensepopularity in both Japan and the United States. The toy is marketedunder the trademark WACKY WALLWALKER in the United States. The toys aremanufactured in an octopus shape and are composed of a sticky,rubber-based composition. When applied to a smooth wall or glasssurface, the octopus-shaped toy appears to crawl down the surface. Therubber is sufficiently sticky to allow the toy to remain attached to thewall. However, the force of gravity pulls the toy down the surface. Asthe toy moves down the surface, it flips and turns and appears to bewalking or crawling in an octopus-like manner.

While the octopus-shaped toys have enjoyed tremendous commercial successas individual items, a substantial market exists for the toys as"premium" items. A "premium" item is a product which is included forfree or at a low cost when another product is purchased.

Premium items are often enclosed with food products, such as popcorn orcereal. Thus, it is important that the premium item be non-toxic, andsafe for inclusion in packages containing products intended for humanconsumption. The prior art rubber-based toys contain significant amountsof benzene or other potentially toxic components. Thus, manufacturers offood products desiring to include the toys product as a premium itemmust resort to expensive packaging of the premium item in order toprotect the food product from potentially toxic materials. Further, evenwhen suitable packaging is used, there remains a danger that the toxicsubstance will migrate through the packaging.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a stickyrubber-based composition which is suitable for use in manufacturingtoys.

It is a further object of the present invention to provide a method formaking a sticky rubber-based composition which is suitable for use inmanufacturing toys.

A still further object of the present invention is to provide anon-toxic, rubber-based composition which contains no benzene or othertoxic substances.

Other objects and features of the present invention will become apparentto those skilled in the art as the disclosure is made in the followingdescription of a preferred embodiment of the present invention asillustrated in the accompanying sheets of drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representation of the mass spectrophotometric analysis ofthe composition of the present invention. FIG. 2 is a representation ofthe mass spectrophotometric analysis of a prior art rubber-basedcomposition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The non-toxic composition of the present invention contains from about40 to about 45% of a synthetic rubber. Although styrene butadiene rubberis the preferred synthetic rubber, any natural or synthetic rubber whichhas the characteristics of styrene butadiene rubber may be used in thecomposition of the present invention. A particularly suitable styrenebutadiene rubber product is manufactured by Shell Chemical Co. and soldunder the tradename Cariflex.

The rubber-based composition of the present invention also contains fromabout 30 to about 35% of a suitable oil, such as paraffin oil ornaphthene oil. About 15 to 25% of ester gum, from about 2 to 8% calciumcarbonate and about 0.2 to 6% of a suitable coloring agent are thenadded to the rubber and oil mixture.

In a preferred embodiment, naphthene oil, sold by Shell Chemical Co.under the tradename Shellflex Oil, is used. A suitable ester gum isavailable from Arakawa Chemical Co. and sold under the tradename SuperEster. Any non-toxic coloring agent suitable for use in manufacturingrubber articles may be used in composition of the present invention.Suitable coloring agents are manufactured by Sumitomo Color Co. in avariety of shades.

The composition of the present invention also may contain metallicparticles and/or phosphorescent material to give the rubber-basedcomposition "glow-in-the-dark" properties.

In accordance with the process of the present invention, the styrenebutadiene rubber is ground to particles having a diameter of less than0.5 millimeters. The oil is added to the rubber, heated to approximately40° to 70° C., and mixed for 10 to 20 minutes. The heating and mixingsteps are important to insure that the oil is blended with the rubberand becomes absorbed by the rubber.

After heating and mixing the oil and rubber until the oil is completelyabsorbed, the ester gum, calcium carbonate, and coloring agent are addedto the oil and rubber mixture.

Upon mixing the remaining ingredients with the rubber and oil mixture,the rubber based composition of the present invention is suitable foruse in manufacturing a desired product. If a toy is to be manufactured,the mixture may be subjected to injection molding at approximately 100to 130 psi, at approximately 160° to 180° C., at a pressing time ofabout 15 to 25 seconds to produce a sticky, non-toxic toy which issuitable for inclusion with a food product.

To facilitate understanding the advantages and operation of the presentinvention, the following example is provided to specifically illustratethe composition of the present invention. Thus, in a preferredembodiment, the composition of the present invention contains:

styrene butadiene rubber: 43%

naphthene oil: 32%

ester gum: 20%

calcium carbonate: 5%

coloring agent: 1%

In a preferred embodiment of the method of the present invention, the32% oil and 43% rubber are heated to a temperature of between 50° and60° C. and mixed for 13 to 15 minutes before the remaining ingredientsare added in the amounts set forth in the preferred embodiment.

The rubber-based composition of the present invention was analyzed bymass spectrophotometry, the results of which are set forth in FIG. 1.The results of a mass spectrophotometric analysis of the compositionused in the prior art is set forth in FIG. 2. As seen in FIG. 1, thecomposition of the present invention contains no benzene or otherpotentially toxic components. However, the composition of the prior artcontains benzene, which renders any article manufactured from the priorart composition unsuitable for inclusion in food products intended forhuman consumption.

Although the composition of the present invention is described as usefulin manufacturing toys, it is understood that the non-toxic rubber basedcomposition may be used to manufacture any article for which thecharacteristics and properties of the composition disclosed anddescribed herein are desirable.

As will be readily understood by those of ordinary skill in the art,minor modifications may be made in the process described without in anyway departing from the spirit and scope of the invention. Accordingly,it is understood that the invention will not be limited to the exactdetails disclosed above, but will be defined in accordance with theappended claims.

What I claim is:
 1. A process for manufacturing a sticky, non-toxicrubber-based toy which comprises the steps of:grinding styrene butadienerubber into particles having a diameter of less than 0.5 millimeters,adding an oil selected from the group consisting of paraffin andnaphthene oils; heating said oil and rubber to a temperature of 50° to60° C.; mixing said oil and rubber for from 13 to 15 minutes so thatsaid oil becomes absorbed by said rubber; adding ester gum, calciumcarbonate and a coloring agent to said rubber and oil mixture, andinjection molding said rubber at a pressure of from about 100 to about130 psi at from about 160° to about 180° C. to produce a sticky,rubber-based toy.